A tire pressure sensor in a Tire Pressure Monitoring System (TPMS) is a coin-cell battery-powered device mounted inside a tire of a vehicle. The tire pressure sensor has a transmitter that periodically transmits tire information to a vehicle-mounted Electronic Control Unit (ECU). The tire pressure sensor also has a receiver, which after the sensor is mounted in a vehicle tire during production, sensor replacement, and/or firmware update, receives from the ECU configuration information.
Conventional tire pressure sensors transmit tire information to the ECU via a Radio Frequency (RF) transmitter at 315 or 434 MHz over a unidirectional wireless channel, but receive information via an energy-efficient Low Frequency (LF) receiver at 125 kHz over a second unidirectional wireless channel. To reduce cost, these two unidirectional wireless channels might be replaced by a single bidirectional wireless channel, such as a Bluetooth Low Energy (BLE) channel.
A problem with the bidirectional wireless channel is the receiving operation consumes too much energy for the tire presser sensor receiver to be powered on continuously. Thus, the receiver is powered on only for short intervals, making immediate communication from the ECU to the tire pressure sensor directly no longer possible. Instead, an operator's hand-held external configuration controller waits for the tire pressure sensor receiver to power up, which could take several minutes, before transmitting configuration information. In a worst-case scenario, the external configuration controller must wait for the entire receiver off time until the tire pressure sensor reacts to a configuration request. If four tires must be configured, then all of these wait times add up to a significant, unacceptable delay.
Tire pressure sensors using BLE wireless channels without a LF receiver exist. However, these tire pressure sensors are retrofit to have a dedicated, high cost receiver, or alternatively, the transceiver transmits directly to a user's smartphone with no integration of the tire information into the vehicle's dashboard. These limitations are due to tire pressure sensors lacking an energy-efficient configuration mechanism, as described herein.